On our chiller we have an automatic drain, but we still drain let it out 2-3 times a day.
At the regulator i drained the air and there was a little water in there, thats why i was thinking that, After we print today i am draining the drain plug under the press itself.
When it indexes , right before it gets to the next station to lift the tables up it shudders a little. The platens going up is not shuddering, Its the movement right before it gets there and when it settles in before it goes up.
It could be the air pressure, but everything looks ok i guess.